The angle at the apex of an isosceles triangle is 75. Find the angle at the base.

A triangle is three points that do not lie on one straight line, connected by segments. In this case, the points are called the vertices of the triangle, and the segments are called its sides.

An isosceles triangle is a triangle in which the sides are equal.

Since in an isosceles triangle the angles at the base are equal, then:

∠А = ∠С.

The sum of all the angles of the triangle is 180º. According to this:

∠А + ∠В + ∠С = 180º;

∠А = ∠С = (180º – ∠В) / 2;

∠А = ∠С = (180º – 75º) / 2 = 105º / 2 = 52.5º.

Answer: The angle at the base of the triangle is 52.5 degrees.